The attorneys for two Oakland contractors charged with bid rigging in an offshoot of the FBI investigations that netted former state Sen. Leland Yee and Chinatown gangster Raymond “Shrimp Boy” Chow are accusing the FBI of conducting a decadelong campaign to entrap African Americans in and out of office in crimes that the agency itself created.

In a court filing this week, the attorneys said the FBI used a “well-paid contract employee” who went by the name William Joseph to “travel around the country and tell racially charged lies to African American citizens and public officials in an effort to entrap those officials into participating in government sting operations.”

The court filing doesn’t name the agent, but in an unusual move states that, “If one simply googles the phrase ‘Possible Government Witness Has Criminal History,’ a photo of the agent, along with his true name” appears.

What pops up is a news story from a Baton Rouge, La., TV station about a “private citizen” who was paid $547,000 by the FBI from 2006 to 2010 to take part in stings in Louisiana and elsewhere. (The “criminal history” refers to another figure involved in the Louisiana case, not Joseph.)

More by Matier & Ross

Dennis Riordan, who made the filing in U.S. District Court in San Francisco along with fellow attorney Martha Boersch, a former federal prosecutor, said they’ve determined that the private citizen was Joseph and that most of the sting targets were, like Joseph, African American.

“It’s a classic case of racial profiling,” Riordan said.

Riordan and Boersch are seeking to have their clients, Oakland construction company executives Len Turner and his brother, Lance Turner, tried separately from six other defendants charged in the case of alleged bid rigging and bribery. The case involves construction contracts at the Lawrence Berkeley National Laboratory and two facilities operated by the state Department of Veterans Affairs.

To back up their charge that the FBI was targeting blacks in the Bay Area, Riordan and Boersch cite the “unsuccessful effort to entrap four African American city council persons in 2013, two in San Francisco and two in Oakland.”

We first reported in April 2014 that an FBI operative posing as an Atlanta developer named William Joseph had met with San Francisco Supervisors London Breed and Malia Cohen — and later with Oakland City Council members Larry Reid and Lynette Gibson McElhaney — claiming to be flush with cash and looking to do business deals. All four officeholders are African American.

The undercover operative expressed interest in doing everything from rehab work for Section 8 housing in San Francisco to building a five-star hotel near the Coliseum complex in Oakland, the officials told us.

Nothing came of the meetings, and none of the officials was accused of wrongdoing.

However, earlier this year, the feds announced indictments against eight defendants in the East Bay — six of whom, including the Turner brothers, are black — who were caught in an FBI sting operation in which Joseph played a key role.

According to an indictment, the Turners engaged in bid rigging for a 2014 contract to renovate a Department of Energy-owned building at Lawrence Berkeley National Laboratory. The Turners allegedly were aided in the scheme by Reid’s son, Taj Reid.

He and the Turners allegedly colluded with a “developer” — the FBI’s operative — willing to pay bribes. The Turners are accused of agreeing to submit a higher bid so the developer could secure the contract with a lower bid.

Separately, Taj Reid and Eric Worthen, a onetime aide to Yee who later became an assistant deputy secretary at the state Department of Veterans Affairs, allegedly accepted $12,000 in bribes from Joseph in exchange for helping him obtain construction contracts at a pair of veterans homes in Southern California.

The Turner brothers, Taj Reid and the other five defendants have all pleaded not guilty.

Asked to respond to the racial-profiling allegations, a spokesman for the FBI in San Francisco said only that the agency “does not target individuals based on race” and referred us to the U.S. attorney’s office for further comment.

Office spokesman Abraham Simmons said federal prosecutors “look forward to addressing the allegations in court” and declined further comment.

Joseph and an undercover FBI agent identified as Mike King helped win federal convictions in 2015 of Yee, for taking bribes in exchange for votes, and former San Francisco school board President Keith Jackson, for helping to set up the bribery scheme and take payoffs himself to traffic in guns and drugs and arrange a supposed murder for hire.

Joseph and King were also part of the case against Chow, who was sentenced to life in prison last year for racketeering and murder.

And both have figured in an attempted bribery case that San Francisco District Attorney George Gascón has brought against against Jackson and former city Human Rights Commission member Nazly Mohajer and former agency employee Zula Jones. The three are charged with soliciting $20,000 in bribes from an undercover FBI agent in exchange for promised political access and preferential treatment in connection with city contracts.

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call (415) 777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross

Whether writing about politics or personalities, Phil Matier and Andy Ross have informed and entertained readers for more than two decades about the always fascinating Bay Area and beyond. Their blend of scoops, insights and investigative reporting can be found every Sunday, Monday and Wednesday in the San Francisco Chronicle.